Cardiac energetics: significance of mitochondria

Summary

The mitochondrial activity as the energy producing step during biological oxidation was observed at rest and its regulation by the energy consuming auxotonic contractile work, depending on the preload, afterload and beat rate in isolated superfused left guinea pig atria. The mitochondrial activity was measured by (1) continuous determination of the O2 uptake rate, (2) the rate of 14CO2 production from labelled glucose or FFA and (3) separate measurements of the atrial ATP-, ADP-, AMP-, CP- and NAD-concentrations, for determination of the energy state. Some results, with points of general interest, are reported and discussed, including this model, former studies about cardiac energetics and the efficiency of cardiac work, reviewed recently [21].